108 BRITISH FRESHWATER RHIZOPODA. 



6. Nebela marginata Penard. 

 (Plate XXVII, figs. 1 and 2.) 



Nebela carinata LEIDY (pars) Freshw. Rhiz. N. Amer. p. 



154, t. xxiv, ff. 6-8. 

 Nebela marginata PENARD Faune Rhiz. Leman (1902), p. 



359, ff. 1-3; AVERINTZEV in Trudui S.-Peterb. Obshch. 



XXXVI (1906), 2, p. 242; SCHOUTEDEN in Ann. Biol. 



Lacustre, I, 3 (1906), pp. 354, 355 ; MURRAY in Ann. 



Scott. Nat. Hist. 1907, p. 95. 



Test chitinous, transparent, not so variable in form 

 as in the preceding species, and larger than average 

 examples of it; the arched crown (in lateral view), 

 and the sides sometimes for a short way below the 

 base of the crown, margined by a narrow keel, less 

 prominent than that of N. carinata ; the edges of the 

 keel more or less irregular in outline. The sides of 

 the test, below the crown, converging in straight 

 (rarely concave) lines downwards to the mouth, which 

 is truncated. The test in narrow lateral view bicon- 

 vex above, strongly compressed, the sides tapering 

 gradually downwards, the mouth being outlined by a 

 shallow notch. The plasma, as in most of the 

 NebelsB, not filling the entire cavity of the test ; attached 

 to the fundus by extensions of its own substance ; the 

 nucleus normally situated and very distinct; the 

 endoplasm containing also variously-sized chlorophyl- 

 lous corpuscles, refringent globules, and some granular 

 material. Pseudopodia five or six in number, digitate, 

 usually simple, and colourless. 



Dimensions: Length 1 40-1 70 /x, ; breadth about 

 120 p. 



In moist Sphagnum, not common. Dunham, Cheshire ; 

 margin of Llyn Idwal, Carnarvonshire, and other 

 localities in North Wales. Moel Siabod, at 2500 ft. 

 (/. Hopldnson}. 



This is liable to be confused with N. tululosa 

 Penard ; it differs from that species in having the 



